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G.E.A.R.: Go-Kart Efficiency through Aerodynamic Research

wind tunnel testing front panels to cut drag on an open wheel kart

project: 05 of 05
event: tjSTAR
credit: Senior research project with two classmates, presented at tjSTAR.

01the problem

open wheel karts churn the air around exposed tires and lose speed to it
the front panel is the first surface the airflow meets
we asked whether shaping it could cut drag without losing the downforce that holds grip

the front panel meets the airflow first

The kart rebuilt in CAD, used as the baseline every panel was tested against. — Fig. 1. The kart rebuilt in CAD, used as the baseline every panel was tested against.

02what governs the problem

drag rises with the square of velocity, so losses grow fast at speed
downforce follows the same square law, which is why the two trade against each other
Reynolds number sets how turbulent the flow around the kart becomes
goal was a panel that performs inside a high Reynolds number regime

flow over the panel, drag pulling back and downforce pushing down

Drag force. — Eq. 1. Drag force.

Reynolds number, which decides whether the flow is smooth or turbulent. — Eq. 2. Reynolds number, which decides whether the flow is smooth or turbulent.

03how we tested

several panel shapes designed in CAD, curved, flat and sloped
cowl and cowl less variants to isolate how much drag the driver adds
each 3D printed and run in a wind tunnel against the bare chassis
drag and front and rear downforce measured across a swept speed range

a model on a force balance in the test section

One of the 3D printed front panels made for wind tunnel testing. — Fig. 2. One of the 3D printed front panels made for wind tunnel testing.

The kart model mounted in the wind tunnel. — Fig. 3. The kart model mounted in the wind tunnel.

04results

the open panel beat the covered panel at every wind speed tested
the driver cover added more drag than the downforce it recovered was worth
the gap widened with speed, matching the square law
CFD agreed with the tunnel, and wide frontal area is the limit to fix next

Measured drag against wind speed for the covered panel and the open panel. — Fig. 4. Measured drag against wind speed for the covered panel and the open panel.